The optimal strength of tretinoin cream for wrinkles depends on individual skin sensitivity and tolerance. Generally, for wrinkles, a strength of 0.05% to 0.1% is recommended. Starting with a lower strength (0.025%) and gradually increasing the concentration over time allows the skin to adjust and minimize potential irritation. However, the most appropriate strength and usage frequency should be determined in consultation with a healthcare professional to ensure individualized treatment and desired results.